1. Technical Field
The technical field relates to hydraulic powered park brake systems.
2. Description of the Technical Field
Park brakes on some vehicles are based on a spring actuated, hydraulic release (SAHR) brake chamber. In such systems the removal of hydraulic pressure results in a spring operating to apply the park brake and the application of hydraulic pressure releases the brake. Examples of such systems powered an engine driven hydraulic pump for the vehicle service brake system are known to the art. Some powered hydraulic service brake systems include an accumulator which provides pressurized hydraulic fluid when the hydraulic pump is unavailable. In systems which provide an accumulator pressurized fluid can be tapped from the accumulator and applied by operator control to release the SAHR chamber from a default, applied condition without operator effort to supply hydraulic system pressure. SAHR brake chambers to support powered park brake systems, while effective, have largely been limited to vehicles with hydraulic foundation brake systems.